Fields of goldfields

The efforts to improve Serpentine Prairie are paying off. Last year I mentioned that the heart of the prairie would be fenced in for a few years. They have also removed the non-native pines that were inappropriately planted. This photo, taken March 28, shows the prairie awash in goldfields. Early summer is the best time to see the rare Presidio clarkia in bloom up there.

Goldfields (Lasthenia spp.) is a very hardy genus that often carpets serpentine soils. Naturally it deserves its name for that alone, but it also has a deeper association with gold. The Mother Lode, running along the western flank of the Sierra Nevada, is a major fault zone, long inactive, that once marked a tectonic suture. Hot gold-bearing fluids rose along the fault and infused the country rock. Serpentinite came up the same way, in the same places. Roadcuts along state route 49 expose lots of it. So where the goldfields blooms, the odds of finding gold are significantly better than chance. Oakland has a great variety of rocks, but no gold that I know of.

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This entry was posted on 31 May 2010 at 3:02 pm and is filed under Oakland's soil. You can follow any responses to this entry through the RSS 2.0 feed.
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4 Responses to “Fields of goldfields”

My name is Ingrid, and I work for Bay Nature magazine. This is gorgeous (the goldfields, I mean). I posted a link to this on our facebook page. We’ve been working on a couple of geology articles for the July issue – one on the rocks of Berkeley, and one on the rocks of Salt Point. Cool!

The pines were fertilizing the soil around them with their litter. Nothing wrong with that, but the Oakland serpentine grounds are a small fraction of their original size, and what’s left needs a bit of care to look its best. In other places, I think planting trees is a great thing. To many people, a serpentine field doesn’t look as prosperous as a forest (not saying that you felt that way, Jef). When the Crestmont neighborhood was allowed to wipe out the western part of the habitat there was less appreciation of the serpentine biome, and I imagine the planners and builders thought they were doing the land a favor.